Speed up Jenkins phpcs (PHP CodeSniffer)

PHP CodeSniffer in our Jenkins CI was always one of the slowest tasks as it ran across our whole code base. LB Denker from Etsy wrote a good piece of software called CSRunner which looked to solve this problem by only running phpcs on files that had changed in the last 7 days (or so). It is written as a PHP script that was run from Jenkins.

I took this idea and adapted it to run in Ant. Instead of looking at files changed in x days, it looks at the checkstyle report from the last run and gets a list of files with problems. It merges this with any files that have changed since the last build. In theory it should bring the run time down (assuming you have a low number of files with problems).

I’m open to any ideas on how to improve this as I’m not that experienced with Ant.